Field
The present invention relates to a cap.
Related Art
Recently, practical applications of vehicles to which a fuel cell which causes electrochemical reactions between fuel gas and oxidizing gas is mounted have been progressed. The oxidizing gas is not necessarily stored in the vehicle because air is used as the oxidizing gas; however, the fuel gas is necessarily stored in the vehicle. Therefore, an art regarding a cap which seals a charging port through which fuel gas is charged into a fuel gas tank of a vehicle is known. For example, JP2007-196920A discloses such a cap which seals a charging port by locking a convex portion provided at an inner wall of the cap, to the charging port.
However, since the convex portion carries all the load which is applied to the cap when attaching the cap to the charging port and when detaching the cap from the charging port in this case, there has been a possibility of wearing out or damaging the convex portion. For this reason, an increase in durability of the convex portion is desired.